The following descriptions and examples do not constitute an admission as prior art by virtue of their inclusion within this section.
During well drilling operations, friction of a drill string against a wellbore may be generated. In particular, horizontal sections of the wellbore may produce higher friction than vertical or directional sections of the wellbore. With the increase in friction, a weight transfer to a drill bit may not be immediately realized, rates of penetration may decline, the drill string and bit wear may be amplified, and productivity may be reduced.
Various drilling tools may be used to attenuate the friction, such as those which induce a vibration, hammering effect, or reciprocation in the drill string. For example, a shock sub may be used with a pressure pulse tool to generate an axial force at a specified frequency, causing an axial vibration which oscillates the drill string and reduces friction. To generate the axial force, the pressure pulse tool may be used to create and apply cyclical pressure pulses to a pump open area of the shock sub. In another example, the cyclical pressure pulses of the pressure pulse tool may produce a water hammering effect, causing the axial vibration needed to oscillate the drill string and reduce friction.
Certain pressure pulse tools may need an external prime mover, such as a mud motor or turbine, in order to produce the cyclical pressure pulses. Implementing these external prime movers may increase the cost and complexity of the well drilling operation. Additionally, a pressure pulse tool utilizing the external prime mover may not allow for wireline accessibility downhole of the pressure pulse tool.